Switching power supplies are aimed to operate at the maximum efficiency by operating at the higher switching frequency. This makes the design deviations and operating tolerance of the switching frequency stringent The operating switching frequency and its stability depends upon the magnetic components used as the part of Switching (Oscillating) element in the switch mode power supply.
Switching Power Supplies are expected to have very high reliability at different operating conditions, such as, Power-On state, Steady state, Load change-over and settling-down, Based design methodologies such as topologies, and Type of converter such as AC/DC and DC/DC.
During these modes of operation the current and voltage characteristics change. It is expected that magnetic components such as inductors, coupled inductors and transformers operate in stable condition such that power supply is not driven to an unstable condition.
For optimum performance, designers generally design magnetic components such as transformers and Inductors using the magnetic characteristics curve, popularly known as a hysteresis curve of the core material, that is supplied by magnetic component manufacturers. Each magnetic component is designed based on the operating voltage, current, topology, and type of converter, In an attempt to ensure that it will operate in the linear region of its hysteresis curve. Unfortunately, there is no mechanism available to verify the design under actual operating conditions.
The operating region of the magnetic components determines the stability of the switching power supply. The power supply operating voltage and current characteristics also depend on Power-on state, Steady state, Load-change state, Type of topology, and Type of converter.
It is extremely difficult, in view of the different scenarios of signal characteristics, to design a magnetic component and ensure that it will operate in a linear region.
What is needed is an apparatus and method to observe and measure the B-H characteristics of the magnetic component in an in-circuit operation.